Maximummer: Black must play the geometrically longest move or may choose from among longest moves of equal length, distances being measured from the center of each square. Diagonal and oblique distances are measured from the orthogonal coordinates by using Pythagora’s theorem (take the square root of the sum of the squares of the orthogonal distances). All other orthodox chess rules apply.

KoeKo: A move is possible only if the piece moved arrives on a square next to another unit.

MAO(MA): The Chinese knight, which is a Rider, moving along a bent line to the arrival square of a normal Knight, first orthogonally then diagonally. The Mao can be interfered with on the intervening square.